Osseointegrated dental implants are typically metallic or ceramic screws that are placed in the jawbone for supporting artificial teeth after the loss of natural teeth. Replacement of the maxillary teeth is often a challenging surgical procedure when the remaining maxillary bone has insufficient height to support the implant. One surgical technique for augmenting the maxillary bone includes injecting a regenerative material, such as autogenic, allogeneic, xenogeneic, or synthetic bone graft, into the vicinity of the maxillary bone. The regenerative material forms additional bone mass that integrates with the existing maxillary bone, providing the necessary alveolar height to support the implant.
Bone augmentation procedures are often surgically difficult to perform, and are associated with complications, including infection of the maxillary sinus. The top of the maxillary alveolar ridge forms the floor of the maxillary sinus, and is covered by a thin membrane known as the Schneiderian or subantral membrane. In one surgical procedure, known as a closed or internal sinus lift or elevation procedure, the surgeon drills a bore through the maxillary alveolar ridge from the oral cavity at the desired location of the implant. The bore penetrates the ridge to below the Schneiderian membrane. The surgeon injects the regenerative material through the bore to below the membrane, forming a cavity defined by the top of the ridge and the bottom of the membrane, which cavity occupies a portion of the space initially occupied by the maxillary sinus.
To prevent potentially serious complications, the surgeon must be careful not to perforate the Schneiderian membrane. This is often difficult, because of the delicacy of the membrane, and the restricted access afforded by the closed approach.
Sotirakis E, in an article entitled, “A different method for elevation of the floor of the maxillary sinus: Experimental study and reference to some cases,” Mediterranean Dental Implant Congress (Athens, Greece), Scientific Programme MDIC (2004), which is incorporated herein by reference, describes a surgical procedure for elevating the antral floor using hydraulic pressure applied with a medical syringe. The procedure was first tested experimentally on hen's eggs as a surrogate sinus, and subsequently on human cadaver preparations.
Chen L et al., in an article entitled, “An 8-year retrospective study: 1,100 patients receiving 1,557 implants using the minimally invasive hydraulic sinus condensing technique,” J Periodontol 76:482-491 (2005), which is incorporated herein by reference, describe an internal crestal approach for performing sinus lift and placing endosseous implants. Sinus burs and condensers of increasing width were used in conjunction with pliable atraumatic bone grafting mixture and hydraulic pressure from a surgical handpiece. The risk of membrane perforation was reduced using the surgeon's tactile skill administered in a two-stage process to first loosen and then graft bone particulate under the Schneiderian membrane. Threaded implants were placed during the same procedure, and secured via primary closure.
US Patent Application Publication 2006/0084034 to Hochman, which is incorporated herein by reference, describes techniques for providing implants in the upper jaw. A sleeve is inserted through the alveolar ridge to the maxillary sinus. The sleeve is used to raise the subantral membrane and form a cavity. A filler, such as a bone growth stimulant, is injected through the sleeve into the cavity. In the process, the sleeve also can cut and/or condense the bone around itself so that the bone can hold an implant. Optionally, the bone growth stimulant is also introduced into the bone surrounding the sleeve. During the injection, the pressure within the sleeve or the cavity is monitored to detect and prevent the rupture of the subantral membrane.
US Patent Application Publication 2006/0172255 to Hochman et al., which is incorporated herein by reference, describes a surgical tool used for preparing a surgical sinus-lift osteotomy. The tool has a defined thread geometry in series with an osteotome tip to cut, crack and push bone from the sinus floor upward into the sinus cavity in a tactual, gentle and controlled motion. The apical osteotome tip is driven into a pre-drilled pilot osteotomy after the cutting threads are engaged and rotated until the sinus floor is cracked free. Once the bony sinus floor is cracked free, a fluid passageway can be pressurized with a sterile fluid at a defined pressure to release and push the sinus membrane upward into the sinus cavity to create a desired apical cavity for grafting.
US Patent Application Publication 2007/0162024 to Siemonsmeier, which is incorporated herein by reference, describes an implant comprising at least one shaft area for anchoring in a bony structure, and at least one opening at the distal end of the shaft area in which the shaft area has a continuous bore extending from the opening to at least one outlet at the apical end, so that targeted introduction of material at least into the periapical area is possible with a stable anchoring in the bone structure even after implantation.
U.S. Pat. No. 5,711,315 to Jerusalmy, which is incorporated herein by reference, describes a method for subantral augmentation including the steps of lifting the Schneiderian membrane from the antral floor, and placing graft material between the Schneiderian membrane and the antral floor, without fracturing the lateral maxillary wall.
U.S. Pat. No. 5,575,650 to Niznick et al., which is incorporated herein by reference, describes a twist-bladed dental drill with an enhanced cutting tip for preparing surgical sites for endosseous implants. The drill includes a central, axially-extending internal passageway for carrying fluid through the shank of the drill to the outer surfaces of the drill.
U.S. Pat. No. 6,758,673 to Fromovich et al., which is incorporated herein by reference, describes techniques for gradual displacing of the periosteal tissue covering bones. The gap developing between the bone and the displaced periosteal tissue will be filled with bone callus as it is in distraction osteogenesis. The techniques allow formation of bone in distraction osteogenesis without cutting a segment of the bone.
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